This study compares two doses of a new COX-2 selective nonsteroidal anti-inflammatory drug, SC-58635, with a standard analgesic agent, propoxyphene napsylate, and with a placebo for the control of postoperative pain in patients hospitalized for procedures on the hip and knee. The primary end point is relief of pain which will be assessed using a standard questionnaire at frequent intervals for the first day and less often for up to five days. Study has been completed and no data are available yet.